1. Prior Art
Burial vaults made of fiberglass or plastic are known. In order to increase the rigidity of such vaults, multiple reinforcing ribs are provided on their surface. Such a structure is found in U.S. Pat. No. 3,159,901 and Canadian patent Nos. 722,356 abd 1,106,160. U.S. Pat. No. 3,545,055 is directed to a coffin having a peripheral outer L-shaped flange provided with apertures for holding the coffin. The flange is essentially intended as a reinforcing rib. The bottom wall is reinforced by a corrugated design. Because the shape of the coffin can vary and particularly the side walls can curve when a cadaver lies on the bottom wall, the cover is provided with a peripheral L-shaped edge to hold the sidewalls from curving. As stated in column 3, line 10, the extension 27 rests in the trough 23 when the cover is opened and this trough extension acts as a hinge for the cover. Such an arrangement does not show nor allow the installation of actual hinges on the sidewall per se and consequently does not allow the sealing and locking with a padlock.